Individualized Accelerated Repetitive Transcranial Magnetic Stimulation Targeting the Inferior Frontal Cortex: A Therapeutic Approach for Refractory Obsessive-Compulsive Disorder
R. Chen, Z. Dong, C. Wu, S. Xiang, W. Liu, V. Voon, Y.-J. ZhaoIntroduction
Obsessive-compulsive disorder (OCD) is a challenging mental health condition with high treatment-refractory rate, prompting increasing interest in developing non-invasive neuromodulation techniques. Repetitive transcranial magnetic stimulation (rTMS) shows effectiveness in OCD targeting anterior cingulate cortex with a deep H7 coil, but with modest efficacy. The inferior frontal cortex (IFC) plays a critical role in inhibition control, which is a key cognitive domain compromised in OCD. Here, we develop a novel accelerated rTMS protocol employing individualized IFC target combined with symptom provocation techniques.
Objectives
This study aims to comprehensively assess efficacy and safety of our accelerated IFC-rTMS protocol in treatment-refractory OCD.
Methods
Eligible OCD participants (DSM-5) were recruited with the following criteria: age 18 to 60; Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) score≥16; failed pharmacotherapy of at least 2 Selective Serotonin Reuptake Inhibitors (SSRI) or 1 SSRI+1 augmentation. Participants with severe psychiatric or neurological comorbidities were excluded. The study is approved by the Ethics committee of the Shanghai Pudong New Area Mental Health Center.
Participants provided personalized distressing images (rated 4-7 on a 0-10 Visual Analog Scale (VAS)) for a subsequent fMRI task to identify personalized target within IFC, involving passive viewing of neutral and provocation images. RTMS was delivered using a liquid-cooled figure-8 coil. The protocol involved thirty 20-Hz stimulation sequences (1200 pulses in 3 minutes (Miron et al. Brain Stimul 2019; 12 1319-1321)), with 6 daily sessions over 5 consecutive days. Stimulation was set at 100% resting motor threshold, preceded by symptom provocation to achieve a VAS distress score of 4-7.
Y-BOCS and Obsessive-Compulsive Inventory-Revised (OCI-R) were assessed at baseline, treatment end and 2 and 4 weeks post-treatment. Treatment response was defined as ≥35% Y-BOCS score reduction.
Results
Eleven participants were recruited and nine finished the treatment. OCD severity was moderate at baseline (Y-BOCS=25.3 ±4.4), with illness duration of 10.7±7.4 years. Both Y-BOCS and OCI-R showed significant differences as a function of treatment (Freidman test χ
2
(3) =11.36, p =0.01; χ
2
(3) =16.36, p<0.001. Fig. 1). The overall response rate at ≥ 1 time point was 66.7%. Adverse events were all mild and self-resolved, including transient headache (n=2), fatigue (n=1) and insomnia (n=1).
Image 1: Long description.